vipune 0.20.1

//! `vipune reindex` handler.
//!
//! Re-embeds rows classified as mock, leaves real rows byte-identical, skips unknown.
//!
//! `--force` (issue #217): model-switch migration path. A thin wrapper over
//! the library's [`crate::migration`] module — the same crash-safe lifecycle
//! the public `vipune::migrate_model` entry point uses (issue #221):
//!
//! 1. Resolve the target profile (unknown id → error, no writes).
//! 2. Pre-flight: token-count every stored row with the passage role.
//!    Any row over the 512-token limit → `Error::MigrationRefused` — no
//!    marker written, no rows changed.
//! 3. Marker first: the migration marker naming the target identity is
//!    (re)written before any row is touched.
//! 4. Re-embed every row (prefix applied exactly once, by the engine).
//! 5. On a fully clean pass the new identity is recorded and the marker
//!    cleared in one transaction → `Ok`. Any per-row failure →
//!    `Error::MigrationIncomplete`; the marker stays and the old identity
//!    is kept.
//!
//! The "Migrating from … to …" / "Resuming interrupted migration to …"
//! banner lines stay in the CLI wrapper — it reads `current_identity` /
//! `is_migrating` before calling the library. Plain reindex (no `--force`)
//! still re-embeds only Mock-classified rows.

use crate::commands::output::{ReindexFailure, ReindexResponse, print_json};
use crate::embedding::{EmbeddingEngine, MAX_EMBEDDING_TOKENS};
use crate::embedding_profiles::{EmbeddingRole, profile_for};
use crate::errors::Error;
use crate::migration::migrate_model;
use crate::sqlite::Database;
use crate::sqlite::embedding::classify_embedding;
use crate::sqlite::identity;
use crate::sqlite::identity::ModelIdentity;
use std::path::Path;
use std::process::ExitCode;
use std::time::Duration;

/// Progress interval: print progress every N rows in human mode.
const PROGRESS_INTERVAL: usize = 50;

/// Open a `Database` handle that fails fast on a locked database, mapping
/// the lock error to the actionable MCP-server hint. `busy_timeout` is set to
/// zero so any contended *statement* fails immediately instead of waiting.
///
/// The `Database::open` itself runs `create_schema`/migrations BEFORE that
/// timeout can be applied, so a contended open waits SQLite's default busy
/// timeout (~5s) and then reports the same actionable message.
fn open_fast_fail(db_path: &Path) -> Result<Database, Error> {
    let db = super::db_busy::open_db(db_path)?;
    db.set_busy_timeout(Duration::ZERO)?;
    Ok(db)
}

/// The migration's config: the CLI's fully resolved config, with only the
/// embedding model re-pointed at the model this command was invoked with.
/// The bin and the library share one `Config` type (issue #267), so there is
/// no field-by-field copy to drift.
fn migration_config(model_id: &str) -> Result<crate::config::Config, Error> {
    let mut config = crate::config::Config::load().map_err(|e| Error::Config(e.to_string()))?;
    config.embedding_model = model_id.to_string();
    Ok(config)
}

pub fn handle_reindex(
    db_path: &Path,
    model_id: &str,
    project_filter: Option<&str>,
    force: bool,
    json: bool,
) -> Result<ExitCode, Error> {
    // Open database (fast-fail on a lock; busy_timeout=0, MCP-server hint)
    let db = open_fast_fail(db_path)?;

    // Determine which projects to process (the full list is also needed for
    // the scoped-reindex hint below).
    let all_project_ids = super::db_busy::wrap_busy(db.list_all_project_ids())?;
    let projects: Vec<String> = if let Some(filter) = project_filter {
        vec![filter.to_string()]
    } else {
        all_project_ids.clone()
    };

    if projects.is_empty() {
        if json {
            print_json(&[ReindexResponse {
                project_id: "(none)".to_string(),
                reindexed: 0,
                skipped: 0,
                failed: vec![],
            }]);
        } else {
            println!("No projects found in database. Nothing to reindex.");
        }
        return Ok(ExitCode::SUCCESS);
    }

    // Human mode, scoped to a single project: nudge the user about the other
    // projects in the store so a scoped reindex doesn't quietly leave them
    // behind (mirrors the issue #156 under-reporting concern).
    if !json && let Some(filter) = project_filter {
        let other_count = all_project_ids
            .iter()
            .filter(|pid| pid.as_str() != filter)
            .count();
        if other_count > 0 {
            println!(
                "Note: {} other project(s) in this database not reindexed. Run with --all-projects to reindex them.",
                other_count
            );
        }
    }

    if force {
        // `reindex --force` is a per-DATABASE migration (issue #217): the
        // marker is written once and the new identity is recorded once, only
        // after every row of every project has been re-embedded. A project
        // filter would leave a silently mixed store, so --force requires
        // --all-projects.
        if project_filter.is_some() {
            eprintln!(
                "Error: `reindex --force` migrates the entire database: pass --all-projects so every project is re-embedded before the marker is written and the new identity is recorded."
            );
            return Ok(ExitCode::from(1));
        }
        return handle_reindex_force(db_path, model_id, &all_project_ids, json);
    }

    // Plain reindex: mock-only classification path.
    let mut total_failed: usize = 0;
    let mut responses: Vec<ReindexResponse> = vec![];

    // Initialise the embedding engine (downloads model if needed)
    let mut engine = EmbeddingEngine::new(model_id)?;

    for project_id in &projects {
        if !json {
            println!("Project {}: reindexing...", project_id);
        }

        // The passage role applies the profile's prefix (e.g. `passage: `
        // under e5) — the engine is the single prefix site.
        let mut embed_callback = |content: &str| {
            engine
                .embed_passage(content)
                .map_err(|e| Error::Inference(e.to_string()))
        };
        // A lock surfacing mid-loop stays a structured `DatabaseLocked` rather
        // than the "just retry" hint: earlier projects have already been
        // re-embedded, so the operator needs the real diagnosis, not a message
        // that reads as a transient failure. Setup paths above fast-fail through
        // `open_fast_fail`.
        let (reindexed, skipped, failed) =
            reindex_project(&db, &mut embed_callback, project_id, json)?;
        let failed_count = failed.len();
        total_failed += failed_count;
        responses.push(ReindexResponse {
            project_id: project_id.clone(),
            reindexed,
            skipped,
            failed,
        });

        if !json {
            println!(
                "  Done: {} reindexed, {} skipped, {} failed",
                reindexed, skipped, failed_count
            );
        }
    }

    print_summary(
        &responses,
        &total_projects_scope(&projects),
        json,
        total_failed,
    )?;
    Ok(ExitCode::SUCCESS)
}

/// `--force` model-switch path (issue #217).
///
/// Thin wrapper over the library's `migrate_model` (issue #221):
///
/// - Open a handle to read the current identity and migration state for the
///   banner, then drop it.
/// - Call `migrate_model` (which opens its own handle with `busy_timeout=0`).
/// - On a per-row failure the marker stays and the exit code is non-zero;
///   on a clean pass the identity is recorded and the marker cleared, and
///   the exit code is zero.
fn handle_reindex_force(
    db_path: &Path,
    model_id: &str,
    projects: &[String],
    json: bool,
) -> Result<ExitCode, Error> {
    // Resolve the profile: the target identity records the profile's pinned
    // revision (not the bge default's), so the marker and the recorded
    // identity both name the model the store will actually be re-embedded with.
    let profile = profile_for(model_id)?;
    let target = ModelIdentity {
        model_id: profile.model_id.to_string(),
        revision: profile.revision.to_string(),
    };
    // The passage prefix, for the pre-flight refusal message.
    let passage_prefix = EmbeddingRole::Passage.prefix(profile).to_string();

    // Read the current identity and migration state for the banner, then drop
    // the handle so `migrate_model` can open its own connection without a
    // lock conflict.
    let (current, migrating) = {
        let db = open_fast_fail(db_path)?;
        let current = identity::current_identity(db.conn()).map_err(Error::from)?;
        let migrating = identity::is_migrating(db.conn()).map_err(Error::from)?;
        (current, migrating)
    };

    if !json {
        if migrating {
            println!("Resuming interrupted migration to {}...", target.display());
        } else if current != target {
            println!(
                "Migrating from {} to {}...",
                current.display(),
                target.display()
            );
        }
    }

    // The migration sees the CLI's fully resolved config, with only the
    // model re-pointed at the one this command was invoked with.
    let lib_config = migration_config(model_id)?;

    // `migrate_model` opens its own handle with busy_timeout=0, constructs a
    // single embedding engine, and runs the full lifecycle with one
    // pre-flight: token scan (no writes when refused), marker-first write,
    // per-project re-embed, then identity + clear marker in one transaction
    // only on a fully clean pass.
    let result = migrate_model(db_path, &lib_config);

    let (reindexed, skipped, failed) = match result {
        Ok(report) => {
            let failed: Vec<ReindexFailure> = report
                .failures
                .into_iter()
                .map(|f| ReindexFailure {
                    id: f.id,
                    error: f.error,
                })
                .collect();
            (report.reindexed, report.skipped, failed)
        }
        Err(crate::errors::Error::MigrationRefused { offending }) => {
            eprintln!(
                "Error: reindex --force refused to start: {} row(s) exceed the {}-token limit once the '{}' passage prefix is prepended. Fix or remove these memories, then re-run `vipune reindex --force`:",
                offending.len(),
                MAX_EMBEDDING_TOKENS,
                passage_prefix.trim(),
            );
            for id in &offending {
                eprintln!("  {id}");
            }
            eprintln!("No migration marker was written and no rows were changed.");
            return Ok(ExitCode::from(1));
        }
        Err(crate::errors::Error::MigrationIncomplete { report }) => {
            let failed: Vec<ReindexFailure> = report
                .failures
                .into_iter()
                .map(|f| ReindexFailure {
                    id: f.id,
                    error: f.error,
                })
                .collect();
            (report.reindexed, report.skipped, failed)
        }
        Err(e) => return Err(e),
    };

    let total_failed = failed.len();
    let responses = vec![ReindexResponse {
        project_id: total_projects_scope(projects),
        reindexed,
        skipped,
        failed,
    }];

    if total_failed > 0 {
        // Any failure means the re-embed pass did not complete; the marker
        // stays (the migration module refuses to record the new identity
        // when the pass is incomplete) so operations refuse until a clean
        // re-run finishes.
        eprintln!(
            "Error: {} row(s) failed during force reindex. The migration marker is left in place; fix the errors and re-run `vipune reindex --force`.",
            total_failed
        );
        print_summary(
            &responses,
            &total_projects_scope(projects),
            json,
            total_failed,
        )?;
        return Ok(ExitCode::from(1));
    }

    if skipped > 0 {
        eprintln!(
            "{} row(s) had corrupted embeddings and were skipped",
            skipped
        );
    }

    if !json {
        println!(
            "Model identity updated to {} (marker cleared).",
            target.display()
        );
    }

    print_summary(
        &responses,
        &total_projects_scope(projects),
        json,
        total_failed,
    )?;
    Ok(ExitCode::SUCCESS)
}

/// Print the per-project JSON / human summary shared by plain and force paths.
fn print_summary(
    responses: &[ReindexResponse],
    scope: &str,
    json: bool,
    total_failed: usize,
) -> Result<(), Error> {
    if json {
        print_json(&responses);
    } else {
        if total_failed > 0 {
            eprintln!("Warning: {} row(s) failed during reindex", total_failed);
            for response in responses {
                for failure in &response.failed {
                    eprintln!("  {} — {}", failure.id, failure.error);
                }
            }
        }
        println!("Total across {}:", scope);
        let reindexed: usize = responses.iter().map(|r| r.reindexed).sum();
        let skipped: usize = responses.iter().map(|r| r.skipped).sum();
        println!("  Reindexed: {}", reindexed);
        println!("  Skipped:   {}", skipped);
        println!("  Failed:    {}", total_failed);
    }
    Ok(())
}

/// Scope label for the summary footer (single project vs all projects).
fn total_projects_scope(projects: &[String]) -> String {
    if projects.len() == 1 {
        format!("project {}", projects[0])
    } else {
        "all projects".to_string()
    }
}

pub(crate) fn reindex_project<F>(
    db: &Database,
    embed: &mut F,
    project_id: &str,
    json: bool,
) -> Result<(usize, usize, Vec<ReindexFailure>), Error>
where
    F: FnMut(&str) -> Result<Vec<f32>, Error>,
{
    let rows = db.list_all_rows_for_project(project_id)?;

    let mut reindexed: usize = 0;
    let mut skipped: usize = 0;
    let mut failed: Vec<ReindexFailure> = vec![];
    let mut processed: usize = 0;

    for (id, content, embedding) in rows {
        processed += 1;

        // Classify
        match classify_embedding(&embedding) {
            crate::sqlite::embedding::EmbeddingClass::Real => {
                // Real row — leave byte-identical
            }
            crate::sqlite::embedding::EmbeddingClass::Unknown => {
                // Corrupted/unknown — skip
                skipped += 1;
                if !json {
                    eprintln!(
                        "  Skipping {} — unknown embedding (norm not in valid range)",
                        id
                    );
                }
                continue;
            }
            crate::sqlite::embedding::EmbeddingClass::Mock => {
                // Re-embed this row
                match reindex_row(embed, &id, &content, db) {
                    Ok(()) => {
                        reindexed += 1;
                    }
                    Err(e) => {
                        failed.push(ReindexFailure {
                            id: id.clone(),
                            error: e.to_string(),
                        });
                        if !json {
                            eprintln!("  Failed {} — {}", id, e);
                        }
                        continue;
                    }
                }
            }
        }

        if !json && processed.is_multiple_of(PROGRESS_INTERVAL) {
            println!(
                "  Progress: {} processed ({} reindexed, {} skipped, {} failed)",
                processed,
                reindexed,
                skipped,
                failed.len()
            );
        }
    }

    Ok((reindexed, skipped, failed))
}

fn reindex_row<F>(embed: &mut F, id: &str, content: &str, db: &Database) -> Result<(), Error>
where
    F: FnMut(&str) -> Result<Vec<f32>, Error>,
{
    let new_embedding = embed(content)?;
    db.update_embedding(id, &new_embedding)?;
    Ok(())
}